Phosphate Ore Research Articles

Synergistic organic manure treatment with Al/Fe/Ca-based fluoride-fixing agents promote soil formation and utilization of phosphate flotation tailings

Soil utilization of phosphate ore flotation tailings (PTs) was achieved using F-fixing agents combined with organic manure treatment to address issues related to inefficient stabilization of P-F, heavy metal solidification/stabilization, poor physicochemical properties, and ecological disruption. The formulation for PTs soil utilization included 1.75 % polyaluminum sulfate (PAS), 1.75 % FeSO4, and 0.25 % CaO, with PTs content at ≥86.75 %. This approach enhanced water retention and improved nutrient and biochemical conditions. Various nutrient indexes met general planting soil requirements: organic matter 24.93 g/kg, available K 252.26 mg/kg, available Ca 2048.67 mg/kg, available Mg 246.13 mg/kg, and ammonia-nitrogen 42.47 mg/kg. The water-soluble P content of PTs-based soil decreased to 6.96 mg/kg, while available P increased to 677.99 mg/kg. Mn leaching toxicity was less than 0.016 mg/L, with a stabilization efficiency of 96.86 %. Water-soluble F in PTs-based soil was reduced to 11.133 mg/kg. This study maximized phosphorus resource utilization and prevented the migration of water-soluble P, F, and Mn to the surrounding environment. Potting experiments showed PTs-based soil was more effective than red soil and PTs-based raw materials in cabbage plantation, achieving a maximum seedling emergence rate of 98.33 %. Microbial diversity increased, and community structure improved in 40-day soil formation experiments, with PTs-based soils developing microbial communities involved in carbon and nitrogen cycling, enhancing resistance to external environmental disturbances, and promoting ecological utilization. These findings offer practical insights into the ecological utilization of large quantities of PTs and present a cost-effective approach for producing planting soils or ecological mulches from similar solid wastes.

Wet grinding effect on the release of phosphate grains and gangue mineral grains of phosphate ores from the Djebel Onk deposit

Wet grinding effect on the release of phosphate grains and gangue mineral grains of phosphate ores from the Djebel Onk deposit

Dissolution Kinetics of Carbonates in Low-Grade Microgranular Phosphate Ore Using Organic Acids as Leaching Agents

Dissolution Kinetics of Carbonates in Low-Grade Microgranular Phosphate Ore Using Organic Acids as Leaching Agents

The selective flotation separation of apatite from dolomite using carrageenan as an innovative bio-based inhibitor

The direct flotation is highly effective in enhancing the quality of concentrate products and removing the content of magnesium for the beneficiation of middle and low grade phosphate ore. This study introduces carrageenan (CG) as an innovative dolomite inhibitor and assesses its effectiveness through micro-flotation tests with sodium oleate (NaOL) as a collector. At pH 10, the combination of 40 mg/L CG and 4 × 10−4 M NaOL successfully separated dolomite from apatite, the artificially mixed ore tests produced a concentrate assaying 32.23 % P2O5 with 76.44 % P2O5 recovery. Results demonstrate CG's strong inhibition of dolomite while minimally affecting apatite. The interaction mechanisms of CG with apatite and dolomite were investigated through various analyses including ICP-OES tests, zeta potential measurements, FTIR tests, contact angle measurements, XPS analysis, AFM tests, and ToF-SIMS analysis. Findings suggest that CG adsorbs strongly to dolomite surfaces by chemisorption between carboxyl groups and Ca sites, whereas it adsorbs weakly to apatite surfaces by hydrogen bonds between carboxyl and hydroxyl groups with F sites. Thus, CG shows promise as an innovative bio-based inhibitor for separating apatite from dolomite using direct flotation.

Laboratory Comparison of Dense Medium Separation and Acid Leaching for Preconcentration of Coarse Rejects from Phosphate Washing Plant

Reverse flotation is a commonly used method for separating carbonate minerals from apatite, but its application to phosphate beneficiation coarse rejects, which are low in P2O5, is often costly due to the high collector dosages used. This study aimed to explore alternative techniques for preconcentration before flotation to improve recovery rates and reduce costs. Our investigation focused on dense medium separation and acid leaching. Dense medium separation, conducted at a cut-off density of 2.76, yielded a preconcentrate with 27% P2O5 and a recovery rate of 90%. The feed material had an initial P2O5 content of 20.52% and a particle size range of +40 µm to −4 mm. In contrast, acid leaching, employing an 8% acetic acid solution over 35 min, yielded a concentrate with 29.11% P2O5, an LOI of 8.99%, and a recovery rate of 100% from an ore fraction [400–200 µm] with an initial P2O5 content of 22.82% and an LOI of 15.78%. Furthermore, integrating flotation and leaching resulted in a concentrate with 32.27% P2O5 and a recovery rate of 98.38%. These findings suggest that combining acid leaching with flotation can enhance P2O5 recovery and reduce processing costs for low-grade phosphate ores.

Recovering rare earth elements from svanbergite ores by roasting and phosphoric acid leaching

Rare earth elements (REEs) are regarded as key global strategic metals, and recovering REEs from phosphate ores might constitute an alternative method of acquiring rare earth resources. Svanbergite ores in Sichuan are particular phosphates rocks that contain abundant REEs, which are valuable resources that have not been fully developed and utilized. Consequently, the development of crucial technologies for extracting REEs from svanbergite ores hold strategic and scientific significance. This study employed roasting and phosphoric acid leaching processes to recover REEs from svanbergite ores. Response surface methodology (RSM) was applied to optimize the hydrometallurgical process parameters. This study found that the optimal conditions for REEs recovery were: a roasting temperature 600℃, a roasting time of 38.72 min, a phosphoric acid concentration of 40%, a leaching liquid/solid mass ratio of 10, a leaching temperature of 75℃ and a leaching time of 70 min, resulting in a maximum predicted REE recovery rate of 83.57%. The experimental values exhibited a high degree of proximity to the predicted values, thereby substantiating the accuracy of the model and validating the plausibility of the optimized solution. Mechanistic analysis revealed that after the roasting process, the crandallite formed new acid-soluble new phases. Following the phosphoric acid leaching process, REEs were present predominantly in the form of REE3+ in the leaching solution, consequently separating the REEs from the svanbergite ores. This study provides a valuable reference for the recovery of REEs from associated rare earth phosphate ores.

Efficient adsorption of sodium oleate from wastewater with graphene oxide/polyethyleneimine composite hydrogel: Performance and mechanism

Sodium oleate (NaOL) is commonly employed as a traditional organic collector during the flotation process of phosphate ore. However, the residual NaOL in mineral processing wastewater not only poses a great threat to the environment, but also reduces the qualities of subsequent flotation products. In this study, an effective adsorbent graphene oxide/polyethyleneimine (GP) composite hydrogel was prepared and applied for the adsorption of NaOL. The successful association between GO and PEI was elucidated through various characterizations. Further to that, the adsorption performance was systematically determined through adsorption isotherm, adsorption kinetics, co-existing ions and reusability experiments. The results clearly demonstrated that the adsorption behavior of NaOL could be well described by both pseudo-second-order (PSO) kinetic and Langmuir isotherm models. GP composite hydrogel was able to achieve superior NaOL adsorption with an excellent adsorption capacity (295.95 mg/g) and a quick kinetic (120 min). The existence of competitive ions, such as CO32−, SO42− and PO43−, had a negative effect on NaOL adsorption. The mechanism investigation suggested that chemical adsorption and hydrogen bonds were central and played imperative roles for the adsorption of NaOL on GP composite hydrogel. Overall, the current work provides a valuable reference for the efficient adsorption of NaOL.

Occurrence, distribution and fate of iodine during phosphate ore beneficiation process

Numerous beneficiation techniques, such as washing, grinding, flotation, digesting, and calcination, are used to concentrate the minerals found in phosphate rocks, which include apatite, carbonatites, and silicates. Significant iodine levels are often found in phosphate ore minerals, which have a distinctive geochemical occurrence. However, the exact occurrence and distribution of iodine in these minerals are not yet thoroughly understood. A study was carried out to investigate the iodine's distribution, occurrence modes (phases), and release rate in Moroccan phosphate as it undergoes the beneficiation process. The samples underwent a multi-analytical approach combining mineralogical and chemical characterization using ICP-MS, ICP-OES, XRD, elements titration, and Pearson correlation analysis for interelement relationships. Calcination, digestion, and Heavy liquid separation is used to study the fate of iodine. The analysis indicates that iodine is primarily found in fluorapatite, with local concentrations ranging from 35 to 130 ppm. The most enriched grains/zones are associated with fluorapatite, enriched in P2O5, F-. in addition, iodine is positively correlated with its main components, including P2O5, F-, SO3, Na2O, CaO, and REEs. The flotation and heavy liquid separation process used for calcite and silicate removal is acting as an iodine and P2O5 concentrator, given that 99 % of iodine occurs in the apatite phase. However, it has been demonstrated that iodine can be released during the digestion of phosphate rock. Where the initial iodine content is distributed among phosphoric acid, PG, and the gaseous phase, constituting 35 %, 25 %, and 40 %, respectively. Furthermore, the calcination of phosphate rock between 800–1000 °C shows that total iodine is released with gases in I2 form, leading to an increase in the concentration of iodine in the surrounding area. In this regard, an integrated pyrometallurgical process has been proposed for the valorization of iodine as silver iodide. This process involves trapping gaseous iodine in an alkaline solution, followed by precipitation, thereby contributing to the overarching objectives of the circular economy and environmental protection.

Reverse cationic flotation of low-grade phosphate ore using quaternary ammonium salt as a collector and its adsorption mechanism

A novel quaternary ammonium salt collector, LH-01, was employed for the reverse cationic flotation of a magnesium-depleted concentrate (P2O5 grade of 19.72wt%, SiO2 content of 44.26wt%). We achieved an outstanding phosphate concentrate with a P2O5 grade of 35.16wt%, a SiO2 content of 6.06wt%, and a P2O5 recovery of 75.88%. This process was accomplished through two sequential reverse cationic flotation processes designed for quartz removal. Importantly, the quartz removal by LH-01 reached 94.17%, far superior to that by dodecyltrimethylammonium chloride, achieving highly selective separation of quartz and apatite. To understand the adsorption mechanism and kinetics of the collector LH-01 on quartz and apatite surfaces, various techniques, such as quartz crystal microbalance with dissipation, atomic force microscopy, and X-ray photoelectron spectroscopy, were employed. Results revealed that the adsorption layer of LH-01 on the apatite surface was thin and rigid, with a significantly lower hydrophobic effect than that of the viscoelastic multiple adsorption layer formed by LH-01 on the quartz surface. This disparity was identified as the primary factor contributing to the selective flotation separation of apatite and quartz. Moreover, the adsorption of LH-01 on the quartz surface was the result of multiple forces, including electrostatic adsorption, multiple-hydrogen-bond adsorption, and intermolecular hydrophobic association.

Revolutionizing Construction: Harnessing Phosphorus Tailings for Lightweight, High‐Strength Wall Materials

AbstractThe beneficiation of low‐grade phosphate ore leads to the production of a substantial quantity of phosphate tailings, thereby not only occupying land but also endangering the environment and potentially posing safety concerns. In this work, extrusion molding, steam‐curing, and calcined phosphate tailings are employed to fabricate lightweight wall materials with superior strength. It is found that the wall material has a special structure of interwoven needle‐like crystals as a way to provide high flexural strength. The main composition of 34.94% phosphate tailings, 36.75% calcined phosphate tailings, 16.64% silica fume, 6.67% anhydrous magnesium sulfate is required to achieve an optimal maintenance process for 4 h of heat preservation at 120 °C saturated vapor pressure environment. The prepared wall materials yield a flexural strength of 24.9 MPa, compressive strength of 18.9 MPa, softening coefficient of 0.81, apparent density of 1.594 g cm−3, and thermal conductivity of 0.269 w/(m K), which meet the requirements of the Chinese standard “Lightweight strip board for building partition walls”. Moreover, the calculation revealed that phosphate tailings have a comprehensive utilization rate of 77.23%, effectively mitigating the issues arising from their accumulation and serving as an efficient means of utilizing solid waste derived from phosphate tailings.

A Critical Review on the Flotation Reagents for Phosphate Ore Beneficiation

A Critical Review on the Flotation Reagents for Phosphate Ore Beneficiation

A rheological study on nano-bubble assisted flotation of phosphate fine particles

ABSTRACT The application of ultrafine bubbles a.k.a. nano-bubbles (NBs) in upgrading the flotation recovery of fine particles has been extensively investigated from various perspectives over the last two decades. However, their rheological aspect has not been studied yet, which is presented for the first time in this paper. To this end, the current study addresses the effect of six crucial variables including solid content (5%, 15%, and 25% (w/w)), presence and absence of NBs, inner diameter of a Venturi tube (1.5 and 2.2 mm), pH of pulp (4.5–11) and frother dosage (3, 13, and 33 mg/L) on the variation of rheological parameters i.e. shear stress, shear tension, and viscosity. Ultrafine bubbles were generated in a conditioning tank through the hydrodynamic cavitation mechanism using a fatty-acid-based frother (Flo-Y-S), while the rheological responses were continuously monitored and measured by a rheometer and parallel plate spindle (for pulp) and a double gap spindle (for NBs). Flotation tests were conducted on a high-grade phosphate ore (d80 = 37 µm) using a mechanically agitated Denver®-type (D12) flotation cell. The experimental results revealed that fluid behavior without NBs using 13 mg/L frother was in the range of shear rates less than 1 s−1 non-Newtonian and close to the shear thinning state, while it became completely Newtonian in the range of 1 to 1500 s−1. However, the presence of NBs at the same frother content changed this tendency to non-Newtonian and Newtonian fluids at shear rates of <30 s−1 and >30 s−1, respectively. It was also found that either in acidic (5.5) or strong alkaline (11) domains, the pulp viscosity trends were almost close to each other and varied from 0.002−10 to 0.002−4 Pa.s, respectively. On the other hand, on the same trend, the amount was lowered to three times in the neutral range (7.5) and weak alkalinities (9). Diminishing the inner diameter of the Venturi tube from 2.2 mm to 1.5 mm led to an increment of shear stress and viscosity about twice at the shear rates <100 s−1. The results of evaluating frother dosage showed that an increase in the amount of frother dosage, which reduced bubble dimensions, exceeded the viscosity and the amount of shear stress. Finally, we concluded that the rheological properties significantly impacted the selective separation of NB-assisted flotation processes and need further investigations in the future.

Effect of dissolved metal ions from mineral surfaces on the surface wettability of phosphate ore by flotation

The dissolved metal ions have a significant effect on the wettability of mineral surface in flotation slurry. In this work, the composition and characteristic of phosphate ore raw (R), flotation concentrate (FC), and flotation tailing (FT), the dissolution of metal ions from mineral surface and its effect on mineral surface wettability were investigated. The results of the dissolution test indicated that the concentrations of Ca2+ and Mg2+ are high (FT > R > FC), while Fe3+ and Al3+ were low in the slurry. H3PO4, as the slurry pH regulator, has the weakest dissolved ability of metal ions from mineral surface compared with HCl, HNO3 and H2SO4. The surface tension tests revealed that metal ions will combine with NaOL in the slurry, causing the consumption of NaOL. The contact Angle tests performed that some of NaOL adsorption sites on the FC and FT surface were covered the hydrolysates of Fe3+ and Al3+, which inhibited the hydrophobicity of the FC and FT surfaces. Ca2+ and Mg2+ consumed part of NaOL in the slurry, inhibiting the hydrophobicity of the FT surface. However, the adsorption of Ca2+ and Mg2+ on the FC surface increased the adsorption of NaOL, which enhanced the hydrophobicity of the FC surface.

Beneficiation of low-grade carbonated phosphate ore by reverse flotation technics using anionic and cationic collectors, Sra Ouertane region, Northwest Tunisia

Beneficiation of low-grade carbonated phosphate ore by reverse flotation technics using anionic and cationic collectors, Sra Ouertane region, Northwest Tunisia

New insights into selective depression mechanism of Tamarindus indica kernel gum in flotation separation of fluorapatite and calcite

The similar floatability of fluorapatite (FAp) and calcite (Cal) lead to difficulty in their separation using fatty acid collectors alone. To effectively recover FAp from Cal, a biodegradable polysaccharide, called Tamarindus indica kernel gum (TIKG), was introduced as an efficient Cal depressant in this study, and its depression mechanisms were elucidated. Flotation tests suggested that in sodium oleate (NaOl) system, TIKG strongly depressed Cal but hardly affected FAp, significantly widening the difference in their floatability. Infrared spectroscopy (IR), zeta potential, and wettability analyses indicated that TIKG had strong adsorption interaction with Cal, hindered NaOl adsorption on Cal, and significantly weakened the hydrophobicity of Cal, while the opposite effect was observed for FAp. X-ray photoelectron spectroscopy (XPS) proved that intense interactions of TIKG with Ca sites of Cal enhanced its adsorption on Cal rather than FAp. Extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) calculations confirmed that TIKG reduced the hydrophobic attraction between Cal and bubbles and enhanced the electrostatic repulsion between them, thereby weakening Cal adhesion to bubbles and depressing Cal flotation. Consequently, TIKG achieved effective separation of FAp and Cal, in which 90.21% of Cal was efficiently removed in addition to 83.58% of FAp recovered. Based on these findings, TIKG serves as a Cal depressant for the purification of Cal-bearing phosphate ores by flotation.

Comprehensive processing of phosphate ores into new types of fused fertilizers

Comprehensive processing of phosphate ores into new types of fused fertilizers

Effects of fertilizer types and application levels on phosphorus availability of saline soils and crops: A meta‐analysis

AbstractPhosphorus deficiency limits agricultural production in saline soils. Phosphorus fertilizer (P fertilizer) affects soil and crop phosphorus availability, water eutrophication control, and rock phosphate ore resource protection. To clarify the effect of varying types and amounts of fertilizers on the phosphorus availability enhancement at different degrees of saline soil and provide theoretical basis for rational fertilization at high salt soil, a meta‐analysis of 257 datasets from 24 studies was conducted. All studies were from Asia and focused on the effects of P fertilizer on the phosphorus availability in saline soils. P fertilizer application increased soil available phosphorus (AP) and total phosphorus (TP) contents by 49.24% and 56.19% (pQ &lt; 0.05). Further sub‐group analysis revealed that the P fertilizer types, application levels, soil salinity, soil alkalinity, and crop species affected the response variables (AP, TP, above‐ground P content, and yield), as well as derived variables such as the proportion of AP to TP content (AP/TP) and the phosphorus fertilizer utilization efficiency. Intermediate‐level pure organic fertilizer enhanced AP content by 55.66%, while high‐level pure organic fertilizer enhanced AP/TP. Intermediate‐level pure organic fertilizer showed the best effects on above‐ground P content and phosphorus fertilizer utilization efficiency. Mineral plus organic fertilizer at this level achieved the highest yield increase (122.34%). Soil phosphorus availability improved more in mild salinity and pH &lt;8.5 soils. Therefore, integrating the overall responses, applying mineral plus organic fertilizer or pure organic fertilizer at an intermediate level (20–60 kg·ha−1·year−1) for 1–2 years could enhance soil AP content, benefit crop growth, and agricultural productivity in saline soils while managing input costs effectively.

Geophysical Assessment of Structurally Controlled Mineral Resources at Wadi El-Nakheel, Eastern Desert, Egypt

It is of great importance to evaluate simple methods to identify mineral occurrence for the future development of society. Applying a reconnaissance magnetic data analysis can help detect the main structural trends mounted to the occurrence of minerals. In this study, geological and geophysical data were analyzed to evaluate the main structural trends affecting mineralization in the area of Wadi El-Nakheel. Geomagnetic data were processed to remove the earth’s magnetic field and reduce the magnetic pole. Some mathematical filters related to detecting and enhancing boundaries between rock units, depending on their magnetization affinity, were applied, including the first vertical derivative, the analytic signal, and 3D Euler deconvolution. After structural analysis of these data, we reached the following findings: The main structural trends from the surface and subsurface estimations were the northwest–southeast trend and the northeast–southwest trend. The orientation and origin of Wadi El-Nakheel are aligned with the main structural trend affecting the area that formed during the Red Sea Rift movement and the Pan-African orogeny. The depth of the deep-seated structure controlling the valley is 1500 m and all mineral occurrence is mainly structurally controlled in the studied area; phosphate ore outcrops are usually aligned with the northwest–southeast geological trend, and metallic ores are related to basement rock succession and the main dominant geological structures in the studied area. Finally, the magnetic method was demonstrated to be a reliable tool for detecting the subsurface boundary between geologic units.

Sustainable utilization of phosphate mine waste rocks as sand substitutes in cement mortar production

The extraction and processing of phosphate ores from sedimentary deposits generates large quantities of mine waste rocks, raising environmental concerns and contributing to landscape disfiguration. This study proposes an eco-friendly approach by exploring the extraction of sand from phosphate waste rocks (PWR) to mitigate the environmental impact associated with the disposal of mine wastes. The investigation focuses on the feasibility of creating masonry cement mortar by incorporating sand obtained from PWR. Three types of sand, Flint (FS), dolomitic limestone (DLS), and phosphate flint (PFS), obtained from the intercalation layers of phosphate were tested as partial replacements for reference sand at varying rates (0 %, 25 %, 50 %, 75 %, and 100 %). The sands were sieved through a 4 mm sieve and characterized to assess their geotechnical, chemical, and mineralogical properties. The toxicity characteristic leaching test analysis was conducted to ensure the environmental safety of recycled sands. Consistent mortar formulations were prepared and cured under uniform conditions. Results showed that a 25 % replacement ratio for each sand type yielded the highest 28-day compressive strengths, exceeding 30.5 MPa. Moreover, the water absorption of mortars decreased from 10.65 % to 8.39 %, 7.29 %, and 5.97 % with the incorporation of 25 % of FS, PFS, and DLS, respectively. Furthermore, toxicity tests revealed that recycled sand met the specified limits for toxic elements Ag, Hg, As, Cd, Cr, Pb, and Zn, and affirmed that incorporating these wastes into MCM significantly reduced the leaching of these metal ions to levels below detection limits (DL=0.01 mg/L). This research contributes to sustainable construction practices by providing a viable solution to minimize mine waste and reduce the construction industry's reliance on natural resources, ultimately addressing both environmental and resource-related challenges.

Analysis of the settling process to improve the quality of phosphate products of the Djebel Onk deposit

The object of the study is the phosphates of the Djebel Onk region, which are part of a vast group of phosphate deposits formed in the Late Cretaceous-Eocene period on the South and Southeast Mediterranean shores. These concentrations of economic interest are operated near the town of Bir El Ater (Tebessa, Algeria). The mining industry based on the extraction and processing of different minerals while respecting the environmental framework plays an important role in the economy of a country. The economic potential of each country will be determined based on the level of production of metals and various mineral substances. In the case of the Djebel Onk phosphate ore, the most dominant mineral in addition to P2O5 is calcium carbonate CaCO3 with more than 50 % in the all-mineral content. In addition, phosphate concentrate contains harmful elements which reduce the value of the market product. Therefore, this study aims to recover the enriched product efficiently and profitably with a minimum of deleterious elements. This work aims to develop a treatment technology with a minimum rejection rate, which allows for achieving production goals and reducing environmental impacts. For this purpose, we proposed an enrichment of these phosphate discharges from the settling process utilizing pneumatic selection (Turbo Separator Ventilate – TSV). The results of the chemical analyses confirm the significant difference in useful and major elements (P2O5) and the minor and harmful elements (MgO). According to the granulochemical analysis of each slice, it is possible to note that the P2O5 content is similar to the various particle-size slices. It is therefore necessary to treat the mass of waste if we want to recover as much phosphate as possible. The obtained X-ray diffractograms highlighted appreciable differences between the raw phosphates and the concentrates, in fact, the qualitative and quantitative variation of the mineralogical species, particularly the calcite, quartz, dolomite, and apatite. TSV is a process used to improve the quality and quantity of phosphate and to eliminate the layer below 0.8 mm. Corresponding to the analyses it was appeared that the P2O5 content 29.5–30 % of the settled product increases to 30.2–31 % after dust removal. Then it is possible to achieve an increase in the quality of phosphate from 63/65 % TPL to 66/68 % TPL.